It's been a while since I got to do one of these...
To say that Díez Díaz et al. (2025) names Petrustitan hungaricus and Uriash kadici is to miss the point. Between the paper itself and the supplementary material, you get a novel's worth of information on the titanosaurs of Romania, including descriptions of a couple dozen significant finds (including individuals and assemblages of multiple individuals). But yes, the report does name one new genus and species, and transfers another species to a second new genus.
Let's start with the old species under a new genus. When we looked at Magyarosaurus back in the day, I didn't even bother trying to separate by the named species. Too many bones, not enough clarity. We met "Magyarosaurus" hungaricus briefly as "the large Magyarosaurus", which is not saying much but is better than M. transsylvanicus, "the other Magyarosaurus". (Also, the type individual wasn't all that much larger than Magyarosaurus dacus, but it's not known from the limited remains whether it was fully grown.) It is based on a left fibula (NHMUK [Natural History Museum of London] R.3853), with an associated left tibia under the same specimen number. This material came from the Sînpetru Formation (or Sânpetru as I've generally seen it before) of the "Sibişel River Valley, south of Sânpetru locality, central Haţeg Basin, Hunedoara County, Romania" (Díez Díaz et al. 2025). Generally fibulae don't receive a lot of credit for diagnostic features, but this one does all right and can even credibly tie another specimen to the new genus and species, one with a fibula plus several caudals, the right ilium, the right radius and ulna, and a metacarpal. This more complete second specimen helps to further differentiate it from M. dacus. The genus name is a multilayered reference, based on the Greek "petra" ("stone"). "Stone titan" is a fitting enough name for a sauropod, but in this case it also links to the formation and to the locality: the "petru" in "Sânpetru" also means "stone" by way of Saint Peter (Díez Díaz et al. 2025). (It's not every paleontology blog that can invoke two different saints in consecutive posts.)
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The lectotype fibula (K–P) and paralectotype tibia (A–F; together with
fibula, G–J) of Petrustitan hungaricus, plus a bonus fibula from
another specimen. Scale bar = 200 mm (7.9 in). Figure 40 in Díez
Díaz et al. (2025).
CC BY 4.0.
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Thus, "Magyarosaurus" hungaricus goes forth from the morass of muddled Magyarosaurus material as a definable species. M. transsylvanicus? Unfortunately, Díez Díaz et al. (2025) were unable to help there. M. transsylvanicus still comes out as indeterminate, and probably the same as M. dacus. (Sorry if anyone was really into M. transsylvanicus.) M. dacus itself gets a spring clean, and three assemblages can be attributed to it. That leaves quite a few that are not yet attached to a species, so there's still a ways to go.
Then there's the new guy, the fabled large-bodied Romanian titanosaur:
Genus and Species: Uriash kadici. Like some other titanosaurs
(e.g.,
Rapetosaurus), the genus name refers to giants of local folklore, in this case the uriaş.
The word can also be used generically for anything gigantic, a bit like the
secondary use of "mammoth" in English. The species name honors Ottokár Kadić,
who was a geologist and paleontologist of the Royal Geological Survey of
Hungary. Kadić discovered the type locality of his future namesake species in
the 1909–1915 time frame (Díez Díaz et al. 2025).
Geography and Stratigraphy: The type specimen comes from Kadić's Locality VI in the Budurone ravine, in the northwest part of the Hațeg Basin in Hunedoara County. Stratigraphically it comes from the lower part of the middle member of the Densuş-Ciula Formation, of early Maastrichtian age (Díez Díaz et al. 2025). This locality has recently been rediscovered (Botfalvai et al. 2021; Díez Díaz et al. 2025).
Holotype: The type and only known specimen is a partial associated skeleton, reposited in the Collection of the Supervisory Authority for Regulatory Affairs in Budapest, Hungary (SZTFH). It consists of four caudals (SZTFH Ob.3090B, D, G, and H; four others are lost), a partial right humerus (SZTFH Ob.3104), a partial right femur and fragment of the left (SZTFH Ob.3103), and left metatarsal I (SZFTH Ob.3095). They share a distinctive dark color and geochemical signature (Botfalvai et al. 2021; Díez Díaz et al. 2025).
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The partial right humerus of Uriash kadici, which figured in the
literature but remained enigmatic for decades. Scale bar = 100 mm (3.9
in). Figure 42 in Díez Díaz et al. (2025).
CC BY 4.0.
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Perhaps "partial associated skeleton" is overselling things a bit on my part. You can get a lot of useful information out of just a few bones, but at the same time, the overall picture of the animal that produced them is still incomplete, leaving us in the realm of tantalizing potential. (Which isn't the worst realm to be stuck in, but it's more the kind of place that's better to visit than to call home.) It's a common problem among titanosaurs, and the challenge is quickly appreciated by a stroll through the section of Díez Díaz et al. (2025) that goes through the various specimens and assemblages. Figure 2 shows a composite skeletal restoration with every bone known for a Transylvanian titanosaur highlighted in red. If a single specimen of that completeness was known, it would be a pretty darn complete titanosaur, particularly from the shoulders back. If each of the four Hațeg titanosaur species defined to date had a specimen of that quality, we wouldn't have any problems dealing with them. (Heck, if just one was that complete, we'd be in much better shape.) Hațeg titanosaurs, though, do not give up their secrets that easily.
Other observations: Size is relative. Uriash kadici, giant of the Hațeg Basin and one of the largest titanosaurs known from Europe, is comparable in size to Epachthosaurus sciuttoi, on the order of 12 m (40 ft) and 8 metric tons (9 US tons). On the other hand, it doesn't take much for a sauropod to look big next to M. dacus, weighing in at less than a metric ton and reaching lengths of less than 3 m (10 ft) (Díez Díaz et al. 2025). (It's hard not to smile thinking of a subcompact sauropod, and I recommend taking a moment to do so now and then.) The authors also note that M. dacus apparently would have been long-limbed and gracile, possibly another change related to island dwarfing. P. hungaricus and Paludititan nalatzensis would have slotted in between the two, closer to M. dacus.
Exactly how U. kadici fit in as a large sauropod on a small landmass is not known: Does it come from a time with lower sea level and a larger habitable area? Does it represent a castaway, more or less? Is it from the beginning of a lineage that had just arrived and had not yet evolved to cope (or not) with the cozy confines (Díez Díaz et al. 2025)? It's hard to tell with one specimen 66+ million years after the fact.
The phylogenetic analyses interestingly find the Hațeg titanosaurs scattered across the galaxy of Titanosauria. This also implies a complex history of arrivals and biogeography, instead of one lineage that set up camp and speciated a bit from time to time (Díez Díaz et al. 2025). Not directly related, but it's something I watch for now: The diamantinasaurs insist on staying just outside of Titanosauria (the ingrates, after I spent all that time writing about them).
References
Botfalvai, G., Z. Csiki-Sava, L. Kocsis, G. Albert, J. Magyar, E. R. Bodor, D. Ţabără, A. Ulyanov, and L. Makádi. 2021. ‘X’ marks the spot! Sedimentological, geochemical and palaeontological investigations of Upper Cretaceous (Maastrichtian) vertebrate fossil localities from the Vălioara valley (Densuş-Ciula Formation, Hațeg Basin, Romania). Cretaceous Research 123: 104781. doi: https://doi.org/10.1016/j.cretres.2021.104781
Díez Díaz, V., P. D. Mannion, Z. Csiki-Sava, and P. Upchurch. 2025. Revision of Romanian sauropod dinosaurs reveals high titanosaur diversity and body-size disparity on the latest Cretaceous Haţeg Island, with implications for titanosaurian biogeography. Journal of Systematic Palaeontology 23: 1, 2441516. doi: https://doi.org/10.1080/14772019.2024.2441516
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